The Antikythera Mechanism – An Ancient Greek Computer

Discovery of the Antikythera Mechanism

At Easter 1900, a group of Greek sponge fishermen were fishing off the coast of the tiny, rocky island of Antikythera, between the southern Greek mainland and Crete. Surfacing after one of his descents, one of the fishermen – Elias Stadiatos, babbled something about a ‘heap of dead naked women’ on the sea bed. Further investigation by the fishermen revealed the 50m long wreck of a sunken Roman cargo ship, about 43m down. The buried objects from the ship included 1st century BC marble and bronze statues (the ‘dead naked women’), coins, gold jewellery, pottery, and what look like lumps of corroded bronze, which broke into several pieces shortly after being brought to the surface.

The finds from the wreck were subsequently examined, recorded and sent off to the National Museum in Athens for display or storage. On May 17, 1902, Greek archaeologist Spyridon Stais was looking through the odd lumps from the shipwreck, covered in marine growth from 2000 years beneath the sea, when he noticed that one piece had a gear wheel embedded in it and what looked like an inscription in Greek.

There had also been a wooden case associated with the object but this, as well as the wooden planks from the ship itself, had subsequently dried out and shrivelled up.

An Ancient Astrolobe?

Further examination and meticulous cleaning revealed additional pieces of the mysterious ancient object, and soon an elaborate geared mechanism made of bronze, and measuring about 33 by 17 by 9 cm, was revealed. Stais believed it the mechanism to be an ancient astronomical clock, but the prevailing opinion at the time was that the strange object was too intricate a device to belong to a wreck dated by the pottery on board to the early 1st century BC. Many researchers thought that the mechanism was the remains of an astrolabe, an astronomical device for observing planetary movements, used for navigation, the earliest known example of which is from 9th century AD Iraq. But no general agreement on the date or purpose of the artefact was reached and the enigma was soon forgotten.

In 1951 Derek De Solla Price, an English physicist who was at the time Professor of the History of Science at Yale University, became fascinated by the complexity of the shipwreck mechanism and began what was to become eight years of detailed study using x-ray photography.

An Ancient Greek Computer

In June 1959, the conclusions of Price’s analyses were published as an article in Scientific American entitled ‘An Ancient Greek Computer’. X-rays of the mechanism had revealed at least 20 separate gears, including a differential gear, previously thought to have been invented in the 16th century. The differential gear allowed the rotation of two shafts at different speeds, as used on the rear axle of automobiles. Price deduced from his research that the Antikythera find represented the remains of ‘great astronomical clock’ which had close ties to ‘a modern analogue computer’. These conclusions met with some unfavourable reactions from scholars at the time, some of whom believed that the object must have been dropped into the sea in medieval times and somehow made its way into the wreck.